This invention relates generally to boring guide fixtures and, more particularly, it relates to a fixture for accurately boring a hole across the width of a wooden plank.
It is a common practice in the industry to join two or more pieces of wood together in edge to edge relationship by boring a hole in each piece and then inserting a dowel into each hole to join the two pieces together. This procedure has been widely used for making picture frames and constructing various kinds of furniture, for example. Depending upon how accurately the holes are drilled in each of the two pieces, a smooth joint of good appearance and quality can usually be achieved.
U.S. Pat. No. 4,449,867 issued to S.J. Dergo on May 22, 1984 discloses a drilling fixture for drilling dowel holes in a workpiece. The fixture includes a flat base plate having a slot therein and a drill guide block having a plurality of bores adapted to guidingly receive a drill bit for drilling a hole in the workpiece. The guide block is pivotally and slideably mounted within the slot so that the guide block can be positioned on top of the base plate at any angle relative to the workpiece. The drill guide bores are arranged in two rows, one on top of the other, so that holes can be drilled at different levels. Spacers are positioned beneath the guide block to raise the drill guide bores above the base plate in those cases where relatively large workpieces are employed. However, it is difficult, if not impossible, to accurately locate the guide bores at a given location on the surface of the workpiece when these spacers are used. Another difficulty with this fixture is that of accurately holding the drill bit in each guide bore so that the drill bit remains steady and does not become misaligned as it passes through the workpiece. This is particularly important in those cases where a long hole is to be bored through the workpiece such as when drilling a hole entirely across the width of a wooden plank.